How to collect data from messages after a specific command?

[DaX0-ex]

Hello everybody!
I got a problem when I started writing my bot on your api.
So, I'm making a user registration system that looks like this:
1 user enters their details with every single post (that's the problem)
the data is then sent to the desired email address and processed by the operators for calls.
Well, I can't understand how, after clicking the conditional button "Start registration"
handle registration data, as it all turns into a mess and the data gets mixed up.

Thank you in advance!

P.S data is collected according to the scheme
Sending a message / receiving a message with data from the user.
And this data must be obtained according to this scheme only after we have pressed the CONDITIONAL button "I want to register".

[DaX0-ex]

Sorry, I just discovered the ability now I know what to do.